Flexible electrode sensor module, preparation method thereof and integrated circuit system

Abstract

The invention relates to the technical field of flexible electronic sensing, and provides a flexible electrode sensor module which comprises a second bonding layer, a supporting layer, a first bonding layer, a conduction layer and a packaging layer which are arranged in sequence, and the supporting layer is attached to the side, away from the packaging layer, of the conduction layer through the first bonding layer; the second bonding layer is arranged on one side, deviating from the conduction layer, of the supporting layer; the conduction layer is made of a conductive fabric, and the packaging layer wraps the edge formed by cutting the conduction layer. On the basis, fiber raveling can be prevented, the electrical property is guaranteed, and meanwhile air permeability and comfort are kept.

Description

Technical Field

[0001] This invention relates to the field of flexible electronic sensing technology, specifically to a flexible electrode sensor module and its fabrication method, as well as an integrated circuit system. Background Technology

[0002] Flexible dry electrodes based on conductive fabrics are a relatively ideal solution for wearable health monitoring, possessing unique advantages such as breathability, softness, and integration into clothing. However, after the conductive fabric is cut and shaped, the conductive fibers at its edges become loose and prone to detachment due to loss of restraint, leading to increased electrode resistance, decreased signal quality, reduced durability, and even a lower signal-to-noise ratio. Existing technologies employ overall coating and encapsulation, which can secure the edges but sacrifices softness and breathability; or they use localized adhesive application at the edges, which does not provide adequate protection for the fibers, still posing a significant risk of detachment, and the adhesive application is prone to cracking due to stress concentration, resulting in low reliability.

[0003] Furthermore, integrating soft conductive fabric electrodes into wearable devices by directly sewing or gluing them together can affect comfort, and during dynamic use, wrinkles can easily form and peel off the substrate, affecting signal stability.

[0004] Therefore, this application studies a flexible electrode sensor module that can prevent fiber detachment, ensure electrical performance, and maintain breathability and comfort. Summary of the Invention

[0005] In order to prevent fiber fraying, ensure electrical performance, and maintain breathability and comfort.

[0006] On the one hand, the flexible electrode sensor module provided in this application adopts the following technical solution:

[0007] A flexible electrode sensor module includes a second adhesive layer, a support layer, a first adhesive layer, a conductive layer, and an encapsulation layer arranged sequentially. The support layer is attached to the side of the conductive layer opposite to the encapsulation layer via the first adhesive layer. The second adhesive layer is disposed on the side of the support layer opposite to the conductive layer. The conductive layer is made of conductive fabric, and the encapsulation layer covers the cut edges of the conductive layer.

[0008] By adopting the above technical solution, a first adhesive layer, a support layer, and a second adhesive layer are stacked in sequence, providing stable mechanical support and a fixed foundation for the flexible conductive layer. This effectively suppresses the risk of the electrode wrinkling or peeling off from the substrate during dynamic use, thereby stabilizing the signal acquisition interface and ensuring electrical performance. Furthermore, the encapsulation layer covers all the cut edges of the conductive layer, effectively fixing the loose conductive fibers at the edges. This fundamentally prevents the problems of increased resistance, signal degradation, and decreased durability caused by edge instability, thus ensuring durability, electrical performance, structural stability, and comfort.

[0009] Optionally, the conductive layer is a conductive fabric formed by an insulating yarn substrate and conductive yarns woven into the substrate, wherein the conductive yarns are distributed in the substrate according to a predetermined pattern to form at least one conductive region separated from the surrounding insulating region.

[0010] By adopting the above technical solution, the insulating substrate ensures electrical isolation of the non-signal acquisition area, while the conductive area with a predetermined pattern distribution ensures the accuracy and efficiency of the signal path; it not only inherits the inherent breathability and softness of textiles, providing a material basis for maintaining comfort, but its structured conductive network also helps to improve the mechanical robustness and electrical stability of the electrodes, further stabilizing the structure and ensuring electrical performance.

[0011] Optionally, the conductive region includes a sensing part for contact sensing, a connection part for signal output, and a connection point region disposed at the end of the connection part. The encapsulation layer covers the edge of the conductive layer in the sensing part and the connection point region, and covers the surface of the conductive layer in the connection part region.

[0012] By adopting the above technical solution, in the sensing part that needs to directly contact the skin to collect signals, the encapsulation layer only covers the edges, maximizing the exposure area of ​​the conductive region and ensuring the sensitivity and quality of signal acquisition. In the connection part that needs to transmit weak electrical signals, the encapsulation layer covers its surface, forming an effective insulating shielding layer to prevent signal leakage, short circuits, or the introduction of external interference, significantly improving the signal-to-noise ratio. In the connection point area where electrical connections are required, the encapsulation layer again only covers the edges, reserving interfaces for soldering or plugging. The differentiated encapsulation effectively solves the problem of edge fiber detachment and achieves coordinated optimization of signal acquisition, transmission, and connection, ensuring high-reliability encapsulation while taking into account the electrical performance of the electrodes and the convenience of integration.

[0013] Optionally, the conductive layer includes a weft layer or a warp layer made of insulating yarn as the base, and conductive yarns as corresponding warp or weft yarns interwoven with the base in a pattern to form the conductive area in the conductive layer.

[0014] By adopting the above technical solution, and by regularly interweaving conductive yarn as one of the warp or weft yarns with the insulating yarn base, a preset conductive pattern can be woven directly, accurately and firmly during the weaving process.

[0015] Optionally, the conductive area is formed by weaving conductive yarns through a jacquard weave, and the skin-friendly contact surface of the conductive layer has a protruding structure.

[0016] By adopting the above technical solution, this protrusion increases the effective contact area and contact pressure between the electrode and the skin surface, which helps to improve the contact interface, reduce contact impedance, and thus improve the intensity and quality of physiological electrical signal acquisition. It can maintain signal quality in dynamic use environment, suppress motion artifacts, further improve signal-to-noise ratio, and ensure electrical performance.

[0017] Optionally, the conductive layer is a three-dimensional knitted structure, with conductive yarns arranged in a pattern on the skin-friendly contact surface of the conductive layer, consisting of at least three consecutive rows or three columns of interlocking loops to form a conductive pattern.

[0018] By adopting the above technical solution, a stable three-dimensional conductive network is constructed on the skin-friendly contact surface. The three-dimensional structure gives the conductive layer better tensile resilience, curved surface fit and structural redundancy, which not only enhances the mechanical durability of the electrode under dynamic bending, but also ensures the overall continuity of the conductive path when the local yarn is stressed or damaged, thereby improving the electrical reliability of the electrode in long-term use.

[0019] On the other hand, the method for fabricating a flexible electrode sensor module provided in this application adopts the following technical solution: A method for fabricating a flexible electrode sensor module includes the following steps: S1: Weaving of the conductive layer: Insulating yarn and conductive yarn are provided and woven by machine weaving or knitting process to form a fabric blank with at least one conductive area; S2: Cutting and edge sealing: The fabric greige is cut into a conductive layer; the cut edges of the conductive layer are sealed by a sealing layer; S3: Lamination and Composition: The second adhesive layer, the support layer, the first adhesive layer, and the conductive layer after edge encapsulation are stacked in a predetermined order; S4: Hot pressing: The stacked layers are hot-pressed together to form the multi-layer structure.

[0020] Optionally, in step S1, the yarn tension is controlled during the weaving process to maintain its elongation at 3% to 10%.

[0021] By adopting the above technical solution, the fabric blank has suitable elasticity and dimensional stability. The appropriate elongation avoids the subsequent processing deformation, dimensional shrinkage or fatigue damage caused by excessive internal stress. It provides a dimensionally stable substrate for the precise cutting and effective packaging of the S2 step, and ensures the dimensional accuracy, shape retention ability and long-term structural stability of the final electrode.

[0022] Optionally, in step S2, a hot cutting process is used to simultaneously complete the cutting and edge melting and sealing at a temperature of 215°C to 265°C.

[0023] By adopting the above technical solution, the hot cutting process utilizes high temperature to melt the fiber at the moment of cutting, realizing the cutting and packaging in one step, which is highly efficient and the packaged body is well integrated with the fabric body, with strong sealing performance.

[0024] Furthermore, the integrated circuit system provided in this application adopts the following technical solution: An integrated circuit system includes the aforementioned flexible electrode sensor module and a signal conditioning circuit electrically connected to the flexible electrode sensor module.

[0025] In summary, this application includes the following beneficial technical effects: 1. By setting up a first adhesive layer, a support layer, and a second adhesive layer stacked in sequence, a stable mechanical support and fixing foundation are provided for the flexible conductive layer, effectively suppressing the risk of the electrode wrinkling or peeling off from the substrate during dynamic use, thereby stabilizing the signal acquisition interface and ensuring electrical performance. Furthermore, the encapsulation layer covers all the cut edges of the conductive layer, effectively fixing the loose conductive fibers at the edges, fundamentally preventing the problems of increased resistance, signal degradation, and decreased durability caused by edge instability, thus ensuring durability and electrical performance, as well as structural stability and comfort. 2. The insulating substrate ensures electrical isolation of non-signal acquisition areas, while the predetermined patterned conductive areas ensure the accuracy and efficiency of the signal path; it not only inherits the inherent breathability and softness of textiles, providing a material basis for maintaining comfort, but its structured conductive network also helps to improve the mechanical robustness and electrical stability of the electrodes, further stabilizing the structure and ensuring electrical performance. 3. In the sensing part that needs to directly contact the skin to collect signals, the encapsulation layer only covers the edges, maximizing the exposed area of ​​the conductive region and ensuring the sensitivity and quality of signal acquisition. In the connection part that needs to transmit weak electrical signals, the encapsulation layer covers its surface, forming an effective insulating shielding layer to prevent signal leakage, short circuits, or the introduction of external interference, significantly improving the signal-to-noise ratio. In the connection point area where electrical connections are required, the encapsulation layer again only covers the edges, reserving interfaces for soldering or plugging. The differentiated encapsulation effectively solves the problem of edge fiber detachment and achieves synergistic optimization of signal acquisition, transmission, and connection, ensuring high-reliability encapsulation while taking into account the electrical performance of the electrodes and the convenience of integration. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0027] In the diagram: Figure 1 This is a schematic diagram of the structure of the flexible electrode sensor module according to an embodiment of this application; Figure 2 This is a schematic diagram of two different shapes of the conductive layer and the encapsulation layer in the flexible electrode sensor module of this application embodiment; Figure 3 This is a schematic diagram of the conductive and insulating regions woven in the conductive layer of the flexible electrode sensor module in this application embodiment; Figure 4 This is a schematic diagram of the three-dimensional structure of the conductive layer braided in the flexible electrode sensor module of this application embodiment.

[0028] Reference numerals: 1. Second adhesive layer; 2. Support layer; 3. First adhesive layer; 4. Conductive layer; 41. Sensing part; 42. Connecting part; 43. Connecting point area; 5. Encapsulation layer; 6. Structural layer; 7. Third adhesive layer. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0030] This application discloses a flexible electrode sensor module. (Refer to...) Figure 1The flexible electrode sensor module includes, sequentially arranged from the side closest to the skin outwards, a second adhesive layer 1, a support layer 2, a first adhesive layer 3, a conductive layer 4, and an encapsulation layer 5. The support layer 2 is attached to the side of the conductive layer 4 opposite to the encapsulation layer 5 via the first adhesive layer 3. The second adhesive layer 1 is disposed on the side of the support layer 2 opposite to the conductive layer 4. The conductive layer 4 is made of conductive fabric, and the encapsulation layer 5 covers the cut edge of the conductive layer 4. A structural layer 6 and a third adhesive layer 7 may also be disposed on the side of the second adhesive layer 1 opposite to the support layer 2, and then bonded to the device, etc., via the third adhesive layer 7. Alternatively, the structural layer 6 may be omitted, and the module may be directly bonded to the device, etc., via the second adhesive layer 1.

[0031] The encapsulation layer 5 is made of thermoplastic polyurethane with a thickness of 0.1 mm. Its shape generally follows the electrode shape, wrapping around the edge of the conductive layer 4 with a width of 1 mm, covering all cut edges of the conductive layer 4. In some areas, it may extend beyond the edge by less than 0.2 mm. The conductive layer 4 is a conductive fabric woven from silver-plated nylon yarn and ordinary nylon yarn at a mass ratio of 10%-20% (13.5%:80%-90% in this embodiment, 86.5% in this embodiment); the silver content is greater than 11% (12.5% ​​in this embodiment). The first adhesive layer 3 is a polyurethane hot melt adhesive film with a thickness of 0.05 mm.

[0032] Due to the tension support of structural layer 6 and support layer 2, and the sealing of encapsulation layer 5, the avalanche oxidation effect caused by excessive stretching and irregular edges is avoided. This results in the encapsulated electrode resistance being ≤0.3Ω / cm. After 30 washing tests, it still meets the requirements of 3M adhesive 180° peel test and 1 kg tensile test, showing no cracks, breaks, or springback in physical appearance, and the electrode performance is normal.

[0033] Electrical connections between connection point area 43 and the FPC can be achieved through welding, riveting, or other methods. Specifically, a homogeneous copper alloy ring with a copper content of 55%-65% is used for three-point alignment of the electrode, FPC, and rivet components. This is followed by pressing, applying pressure, and holding the pressure to ensure the copper alloy ring penetrates the surfaces of the FPC and electrode, forming an electrical riveting structure with the cross-section of the conductive material of the electrode and FPC. If welding is used, the protruding pads of the electrode between the FPC components are electrically connected and fixed using solder. After riveting or welding, exposed rivets or solder can be isolated from the outside environment using structural materials or resins such as foam adhesive or epoxy resin.

[0034] In some embodiments, the conductive layer 4 is a substrate made of insulating yarn and a conductive fabric formed by conductive yarns woven into the substrate, wherein the conductive yarns are distributed in the substrate according to a predetermined pattern to form at least one conductive region separated from the surrounding insulating region. Figure 3In the weaving process, conductive fabric is used in the middle of the weft knitting yarn to form a conductive layer 4 with conductive area, insulating area, conductive area, insulating area, etc. arranged in sequence. The warp knitting yarn forms an insulating cover on the weft knitting yarn along the arrangement direction of the conductive area and the insulating area. The conductive area is located between the two sets of insulating covers.

[0035] In some embodiments, the conductive region includes a sensing portion 41 for contact sensing, a connection portion 42 for signal output, and a connection point region 43 disposed at the end of the connection portion 42. The encapsulation layer 5 covers the edge of the conductive layer 4 at the sensing portion 41 and the connection point region 43, and covers the surface of the conductive layer 4 in the connection portion 42 region.

[0036] In some embodiments, the conductive layer 4 includes a weft layer or a warp layer made of insulating yarn as the substrate, and conductive yarns as corresponding warp or weft yarns interwoven with the substrate in a pattern to form the conductive area in the conductive layer 4.

[0037] In some embodiments, the conductive area is formed by conductive yarns woven with a jacquard weave, and the skin-friendly contact surface of the conductive layer 4 has a protruding structure.

[0038] In some embodiments, the conductive layer 4 is a three-dimensional knitted structure. Conductive yarns are interlocked in at least K ≥ 3 rows or 3 columns of loops on the skin-contact side of the conductive layer 4 according to a pattern, and tension is applied to ensure that contacts are formed between every k+1 layers of the 3 rows or columns of fabric, thereby forming a conductive pattern. In areas outside the conductive pattern, the conductive yarns are located on the back or inner layer of the knitted structure. The formation of looped contacts increases the number of contacts in the two-dimensional upper and lower layers by at least two, thereby increasing the number of contacts in the conductive network from [previous figure]. At least This leaves more space for current conduction in the conductive path, improving conductivity. Theoretically, the number of contacts is far greater than... .

[0039] After the modules prepared using this method are assembled into a complete machine, and after 30 machine washes, they still meet the original factory breaking strength and elongation specifications in GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)" and the appearance smoothness level specified in GB / T 13769-2009 "Textiles - Test Method for Assessing the Appearance Smoothness of Fabrics After Washing" are at the same level as the factory level.

[0040] The implementation principle of a flexible electrode sensor module in this application embodiment is as follows: a first adhesive layer 3, a support layer 2, and a second adhesive layer 1 are stacked in sequence to provide stable mechanical support and a fixed foundation for the flexible conductive layer 4, effectively suppressing the risk of wrinkles or peeling from the substrate during dynamic use, thereby stabilizing the signal acquisition interface and ensuring electrical performance; and the encapsulation layer 5 covers all the cut edges of the conductive layer 4, effectively fixing the loose conductive fibers at the edges, fundamentally preventing the problems of increased resistance, signal degradation, and decreased durability caused by edge instability, thus ensuring durability and electrical performance, as well as structural stability and comfort.

[0041] This application also discloses a method for fabricating a flexible electrode sensor module. The method for fabricating a flexible electrode sensor module includes the following steps: S1: Weaving of the conductive layer 4: Insulating yarn and conductive yarn are provided, and woven by machine weaving or knitting process to form a fabric greige with at least one conductive area; during weaving, conductive material is used intermittently in warp knitting, and conductive material is not used in weft knitting; or conversely, conductive material is used intermittently in weft knitting, and conductive material is not used in warp knitting.

[0042] In some embodiments, the density and elasticity of the conductive layer 4 are controlled by adjusting the weaving process parameters to adapt to different application scenarios.

[0043] In weaving, when the weft density is controlled below 160 threads / 10cm, the take-up speed is faster, resulting in a lower density fabric. When the weft density is controlled between 160 and 280 threads / 10cm, with a medium-sized reed, the total fabric tightness is controlled at 60% to 80%, resulting in a medium-density fabric. When the weft density is greater than 280 threads / 10cm, with a high-sized reed, the total tightness is greater than 90%, resulting in a higher density fabric.

[0044] In knitting processes, a lower density fabric can be obtained when the loop length is 13.4~13.5cm / 50 stitches; a medium density fabric can be obtained when the loop length is 31cm / 100 stitches and the transverse density is 40 loops / 25.4mm; and a higher density fabric can be obtained when using parameters of 4684 total needles, 748mm cylinder diameter, 92F loops, and 15r / min speed, and interlacing non-conductive fabric and silver-plated conductor yarn in a 4:1 ratio.

[0045] During the above weaving process, the yarn tension is controlled to maintain its elongation at 3% to 10% to ensure that the fabric has suitable elasticity and dimensional stability.

[0046] S2: Cutting and edge sealing: The fabric greige is cut into conductive layer 4; the cut edges of the conductive layer 4 are sealed by sealing layer 5; In step S2, a hot cutting process is used to simultaneously complete the cutting and edge melting and sealing at a temperature of 215°C to 265°C.

[0047] S3: Lamination and composite: The second adhesive layer 1, the support layer 2, the first adhesive layer 3, and the conductive layer 4 after edge encapsulation are stacked in a predetermined order; S4: Hot pressing: The stacked layers are hot-pressed together to form the multi-layer structure.

[0048] This application also discloses an integrated circuit system. The integrated circuit system includes the aforementioned flexible electrode sensor module and a signal conditioning circuit electrically connected to the flexible electrode sensor module. When used for collecting EEG information, the flexible electrode module serves as a data electrode, a reference electrode, a right leg drive electrode (DRL) electrode, and a ground electrode. The signal conditioning circuit includes a first-stage amplifier and a second-stage amplifier. Both the reference electrode and the data electrode are connected in series to the same second-stage amplifier with a high common-mode rejection ratio (CMRR) after passing through a first-stage amplifier with a low CMRR. The output of the second-stage amplifier forms a common-mode negative feedback loop with the reference input. Therefore, the effective CMRR can exceed the CMRR values ​​of each stage amplifier. For example, if the first-stage amplifier has a CMRR of 66dB and the second-stage amplifier has a CMRR of 115dB, then the effective CMRR is >115dB.

[0049] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0050] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0051] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A flexible electrode sensor module, characterized in that: The assembly includes a second adhesive layer, a support layer, a first adhesive layer, a conductive layer, and an encapsulation layer arranged sequentially. The support layer is attached to the side of the conductive layer opposite to the encapsulation layer via the first adhesive layer. The second adhesive layer is disposed on the side of the support layer opposite to the conductive layer. The conductive layer is made of conductive fabric, and the encapsulation layer covers the cut edges of the conductive layer.

2. The flexible electrode sensor module according to claim 1, characterized in that: The conductive layer is a conductive fabric formed by an insulating yarn substrate and conductive yarns woven into the substrate, wherein the conductive yarns are distributed in the substrate according to a predetermined pattern to form at least one conductive region separated from the surrounding insulating region.

3. The flexible electrode sensor module according to claim 2, characterized in that: The conductive region includes a sensing part for contact sensing, a connection part for signal output, and a connection point region disposed at the end of the connection part. The encapsulation layer covers the edge of the conductive layer in the sensing part and the connection point region, and covers the surface of the conductive layer in the connection part region.

4. The flexible electrode sensor module according to claim 2, characterized in that: The conductive layer includes a weft layer or a warp layer made of insulating yarn as the base, and conductive yarns as corresponding warp or weft yarns interwoven with the base in a pattern to form the conductive area in the conductive layer.

5. A flexible electrode sensor module according to claim 4, characterized in that: The conductive area is formed by weaving conductive yarns through a jacquard weave, and the skin-friendly contact surface of the conductive layer has a protruding structure.

6. A flexible electrode sensor module according to claim 2, characterized in that: The conductive layer is a three-dimensional knitted structure. The conductive yarns are arranged in a pattern on the skin-friendly contact side of the conductive layer, with at least 3 consecutive rows or 3 columns of loops interlocking to form a conductive pattern.

7. A method for fabricating a flexible electrode sensor module as described in any one of claims 1-6, characterized in that: Includes the following steps: S1: Conductive layer weaving: Insulating yarn and conductive yarn are provided and woven by machine weaving or knitting process to form a fabric greige with at least one conductive area; S2: Cutting and edge sealing: The fabric greige is cut into a conductive layer; the cut edges of the conductive layer are sealed by a sealing layer; S3: Lamination and Composition: The second adhesive layer, the support layer, the first adhesive layer, and the conductive layer after edge encapsulation are stacked in a predetermined order; S4: Hot pressing: The stacked layers are hot-pressed together to form a multi-layer structure.

8. The method for fabricating a flexible electrode sensor module according to claim 7, characterized in that: In step S1, the yarn tension is controlled during the weaving process to maintain its elongation at 3% to 10%.

9. The method for fabricating a flexible electrode sensor module according to claim 7, characterized in that: In step S2, a hot cutting process is used to simultaneously complete the cutting and edge melting and sealing at a temperature of 215°C to 265°C.

10. An integrated circuit system, characterized in that: It includes the flexible electrode sensor module as described in claims 1-6, and a signal conditioning circuit electrically connected to the flexible electrode sensor module.

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